This invention relates to a device for picking up semirigid sheet-like elements from a magazine and transferring them onto a conveyor. The invention is specially useful for picking up and opening closed or flattened cases or containers in packaging systems. It is known that in the container field for product packaging use is made of cases which are picked up at intervals from a fixed magazine wherein they are contained in stacked arrangements.
In order to extract such cases from the magazine, various approaches have been proposed which comprise a wheel mounted for rotation about a horizontal axis and carrying gripping members arranged peripherally, which are effective to retain the cases that are individually picked up from the magazine and transferred onto the wheel by auxiliary means.
Such auxiliary means usually consists of reciprocating suckers or pushers which withdraw the front case from the magazine and bring it into the gripping means range, such means then releasing it onto a conveyor after performing a given rotation. In the prior art apparatus, the cases are either opened during said rotation or as they are delivered to the conveyor.
Prior art apparatus are affected by substantial shortcomings. First of all, owing to the relative speed between the wheel and magazine, it is somewhat difficult to achieve good accuracy in picking up and positioning the cases onto the gripping means. Secondly, the cases are opened by applying suitable pressure forces to the opposite edges of the closed cases or, alternatively, by means of pushers which compress the folds which make up the case. These shortcomings, in actual practice, reflect in an appreciable limitation to the rate of production of prior art apparata, as well as in faulty and unreliable opening of the cases, and especially so when the latter are of a material of square section exhibiting poor rigidity.